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Black Widow Spider

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Haley Pest Control of Lawrence Can Help Rid Your Home of Black Widow Spiders 

Black Widow Spider venoms contain toxins that attack our nervous system (neurotoxins), usually by interfering with nerve impulse transmission, so disrupting many of the body's functions. In extreme cases, this can result in death due to respiratory or circulatory failure.

The widow spiders characteristically spins tangled webs, which look similar to spun cotton candy. Their webs are usually built in or beneath objects close to the ground such as under porches, under foundations of buildings, the lose bark of trees, and in basements. The bite of the black widow is painful and may cause death if medical attention is not sought immediately.



The venom of this spider is highly neurotoxic and respiratory failure can occur if appropriate medications are not administered at once. Fortunately, the black widow is shy and does not bite without great provocation. The spider normally resides in an coarse, irregular web. The adult female spider will bite if she feels her young are in danger. If bitten by a black widow place ice wrapped in a washcloth or other suitable covering However, it is essential to seek immediate emergency medical treatment.

The Black Widow Spider along with the Brown Recluse or fiddle-back spider - Loxosceles reclusa - are the two most poisonous spiders found in the United States Widow spiders belong to the cobweb spider family and spin loosely organized trap webs. The webs are usually found under objects such as rocks and ground trash or under an overhanging embankment. Black widow spiders are not as common in homes as the brown recluse. When found in homes, they are usually under appliances or heavy furniture and not out in the open like other cobweb spiders. Black widow spiders are timid, however, and will only bite in response to being injured. People are usually bitten when they reach under furniture or lift objects under which a spider is hiding.

Black widows belong to the Family Theridiidae, a group of spiders known as the comb-footed spiders because of the specialized comb structure on tarsus IV. This comb is used to create the characteristic tangled web as exemplified by the domestic cob-web spider (Achaearanea tepidariorum) found in many houses throughout the US.

The Black Widow spider rarely, if ever, builds their cob-webs inside a house. Black widow webs are an irregular tangled mesh built in dark spots sheltered from the weather. Typical web sites include spaces under large rocks or logs, in holes in dirt embankments and occasionally in barns, outhouses (always check under the seat), and other out-buildings. Females may occasionally kill and eat a male after mating but this is more the exception than the rule. After mating, females will lay several egg masses (gray or tan/yellow depending upon the species) in the web. Females can produce egg sacs the following year with some females having the good fortune to live and reproduce up to three years.

Bite Symptoms

Black widow venom is a nerve toxin and its effects are rapid. After being bitten from a black widow one may feel painful rigidity in the muscles of the abdomen and a feeling of tightness in the chest. Other symptoms include an increase in blood pressure, a rise in body temperature, nausea, and sweating. Death is uncommon (less than 1% of the reported cases), but in the elderly or very young death may occur from asphyxia 14-32 hours after being bitten.

First aid for black widow spider bites involves cleaning the wound and applying ice packs to slow absorption of venom. Victims should seek medical attention promptly. Most black widow spider envenomation respond to intravenous administrations of calcium gluconate or calcium salts. An anti-venom is also available for severe cases.

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